Process of manufacturing molded objects.



ATENT OFFICE.

.lARIi GEllNZl VEIG, OF LUDIVIGSI'IAFEN, GERMANY.

PROCESS OF MANUFACTURING MOLDED OBJECTS.

SPECIFICATION forming part of Letters Patent No. 642,223, dated January 30, 1900.

Application filed November 7, 1898. Serial No. 695,781. specimens) To (til whom it YH/(LZ/ concern:

Be it known that I, CARL GRiiNZWEIG, doc tor of philosophy, a subject of the King of Bavaria, residing at Ludwigshafen'on the- Rhine, Bavaria, Germany, have invented cerfain new and useful Improvements in Processes of Manufacturing Molded Objects Impervious to Heat and Water and of any Dimensions from Cork or Plant Marrow, (for which I have applied for a patentin Germany, dated April 21, 1898,) of which the following is a specification.

Practice has shown that a material intended for protecting bodies whose temperature is under 32 Fahrenheit against the influence of heat must be perfectly waterproof, for as soon as there is any possibility of the circumalnbient air penetrating the material the dew-point is reached and the Water which condenses renders the latter unfit for use if it is not waterproof. Coating the material with hydrofuge substances, such as pitch and the like, having proved unreliable it has been made, for instance, of finely-divided cork coated with hot liquid tar, asphalt, rosin, and the like on its outer surface and molded under a greater or less pressure, whereby the envelop of tar, &c., acts at the same time as binding material in the object thus molded. (See British Patents No. 7,933 of 1888 and No. 663 of 1880.) These objects are indeed waterproof, but they have the disadvantage that under the influence of heat they get out of shape and swell if they have been made under a sufficientlystrong pressure. This may occur, for instance, during transportation in the hot season or freighting to the tropical regions or when the objects so covered are exposed di-. rectly to the action of the solar rays or, again, have been blown through with steam for the purpose of cleaning them and upon the whole whenever the material is subjected to a high temperature.

By my improved process I am enabled to produce a material which is both water and heat proof. The process will be described as it will be carried out in the manufacture of a cork stone.

The particles of cork are first covered with a binding material which is a non-conductor of heat, but is not waterproof, such as an emulsion of clay and tar, and the mixture is then formed into the desired shape by mold ing without being subjected toheavy pressure, only sufficient pressure being employed to cause the cork particles to adhere together, so as to form a compact mass. Now as long as this mass remains absolutely dry it will resist high temperature and also any tendency to rupture. The binding material and cork are not impervious to either water or air, and consequently moisture penetrating the pores of the binding material will be absorbed by the cork particles and cause the latter to swell, sometimes to a sufficient extent to disrupt the stone, and in all cases destroying the nonheat-conducting qualities of the stone. It is therefore necessary to make the binding material which surrounds the cork particles waterproof, and it is not sufficient to do this on the surface of the stone only, but throughout the entire mass. If the Waterproofing material be employed on the surface only and the stone should have a chip or piece broken off the surface, the binding material in its normal condition would be exposed to the action of the air, and perhaps water, and it would be a very short period before moisture in the air or the water would penetrate the entire mass and destroy the usefulness of the stone. In carrying out my process I immerse the mass formed of cork particles and binding material in hot liquefied pitch or other equivalent waterproof materialas rosin, asphaltum, &c.-and keep it immersed until the waterproofin g material has completely saturated the mass and filled the pores of the binding material around all the cork particles. To effectually do this, the waterproofing material must be under some pressure, the extent of which will depend upon the dimensions of the article treated. If the piece is of small dimensions, the pressure due to the head of waterproofing material resting on the article will be sufficient. With large articles an artificial pressure amounting to several atmospheres will be necessary, and frequently it will be necessary to exhaust the air from the vessel in which the Waterproofin g is to be done before introducing the liquid waterproofing material. By this process I produce a cork stone which is both water and heat proof.

Having described the invention, I claim- 1. The process herein described which con about said article, and then applying a waterproofing liquid to the article and maintaining the liquid under pressure in contact with the article until the pores of the binding material are completely filled up throughout the mass, substantially as set forth.

In Witness whereof I have hereunto signed my name in the presence of two subscribing witnesses.

CARL GRUNZWEIG.

WVitnesses (J. MEssER, J. ADRIAN. 

